Amps ↔ Watts

P ≈ V × A × PF (PF defaults to 1.0 for resistive loads). For DC, PF = 1.

Voltage (V)

Power Factor (PF)

  Reset

Amps (A)

Watts (W)

Watts ↔ kWh (with Hours)

Energy (kWh) = Watts × Hours ÷ 1000.

Watts (W)

Hours (h)

kWh

Calculate

Tip: leave either Watts or kWh blank to solve for it.

Cost Estimator

Cost = kWh × Rate. Add demand or fees separately if needed.

Energy (kWh)

Rate ($/kWh)

Days (optional)

Calculate

If days is provided, monthly/annual will be estimated.

Battery Bank Sizing

Given your daily energy use, system voltage, desired autonomy, depth of discharge (DoD) and round‑trip efficiency.

Daily Use (kWh/day)

System Voltage 12 V 24 V 48 V

Days of Autonomy

Allowable DoD (%)

Battery Round‑Trip Eff. (%)

Nominal Module (V × Ah) 12 V 100 Ah 12 V 200 Ah 24 V 100 Ah 48 V 100 Ah Custom…

Custom Module (V and Ah)

Calculate

Rule of thumb DoD: LiFePO₄ ≈ 80–90%, AGM ≈ 50%.

Solar Array Sizing

Array Watts ≈ Daily kWh ÷ (Sun Hours × System Derate). Derate accounts for temperature, wiring, dust, etc. (default 0.75).

Daily Load (kWh/day)

Sun Hours (peak‑sun h)

System Derate (0–1)

Panel Wattage (W)

Calculate

Result shows total array watts and an estimated panel count.

Inverter DC Current

DC Amps ≈ AC Watts ÷ (Battery Volts × Inverter Eff.).

AC Load (W)

Battery Voltage (V) 12 V 24 V 48 V

Inverter Eff. (0–1)

Calculate

PV Series/Parallel

Compute array Vmp/Voc and Imp/Isc from a panel’s datasheet values.

Panel Vmp

Panel Imp

Panel Voc

Panel Isc

Panels in Series

Series Strings in Parallel

Cold Multiplier (Voc)

Approx. for winter temps (e.g., 1.10–1.25)

Calculate